In the field of dentistry, the dispensing of various dental materials directly to a tooth surface to effect a tooth restoration has been known for some time. Reference is made to the placement of relatively high viscosity materials, e.g. filled composite resin material, directly to the site of the restoration using a syringe technique as disclosed in U.S. Pat. Nos. 3,518,399; 3,900,954 and 4,198,756. These patents disclose the syringing technique of utilizing a capsule filled with a high viscosity composite material from which the material was extruded by the displacement of a piston by means of a syringe or syringe gun.
Subsequently, others have adopted the technique of syringing the heavy or high viscosity dental materials as disclosed in U.S. Pat. Nos. 4,330,280 and 4,384,853. As the syringing technique and the use of unit dose capsules for dispensing heavy viscosity dental materials has gained recognition as the preferred method of placing heavy composite dental materials, various other capsule configurations have been made, as evidenced by U.S. Pat. Nos. 4,391,590; 4,619,613; 4,767,326; 4,963,093; 4,969,816; 5,100,320; 5,322,440 and 5,460,523, to cite a few. While the syringing technique and the use of preloaded capsules of the various known constructions proved satisfactory for the placement of heavy viscosity composite materials, difficulty has been encountered when using the syringe and capsule technique with the more fluent or very low viscosity dental materials that have a liquid state, as distinguished from the heavy viscosity dental materials that have a heavy paste-like consistency. This is because dental material having a very fluent liquid state could not be readily contained within the capsule as the material would tend to leak out of the capsule by gravity. Further, if the liquid or very fluent dental materials could be retained within the capsule, the dentist could not control the discharge of such liquid material from the capsule by syringing. As a result, the known capsule constructions were not generally suitable for dispensing very fluent or low viscosity dental material, e.g. those dental materials having a liquid-like consistency. For these reasons, dentists had to apply such fluid material by means of a brush or other suitable manual applicator, which required the dentist to repeatedly dip the brush or applicator into the fluid dental material, and then apply the material to a tooth, a tedious and time consuming procedure.